When Feynman said that a concept was "more mathematical" or "more abstract," he was not paying a compliment!  He had no use for theory devoid of physical content. In the Lectures on Gravitation, he says:

If there is something very slightly wrong in our definition of the theories, then the full mathematical rigor may convert these errors into ridiculous conclusions.

We called that "carrying rigor to the point of rigor mortis."

-- Carver A. Mead, Collective Electrodynamics